Blur-Calibration System Using Moving Multi-Target Constellation

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Solution Overview

Problem

Conventional methods for blur-calibration of imaging sensors, especially in cryo-vacuum conditions, are time-consuming, costly, and limited in accuracy, making it difficult to precisely measure the point-spread function (PSF) across the field-of-view (FOV) of imaging sensors.

Innovation Solution

A blur-calibration system using a moving multi-target constellation is employed, where a known target pattern is moved across the FOV, capturing frames at different pixel phases, and the image data is processed to generate high-resolution composite images. Chopper modulation is applied to separate chopper-open and chopper-closed composite images, allowing for the determination of the PSF and specification of blur shapes at various locations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional blur-calibration methods are used in cryo-vacuum conditions, then calibration can be performed, but the process is time-consuming, expensive and limited in accuracy

Engineering Contradiction:
ImprovePSF measurement accuracyVSAvoidcalibration time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent employs a moving target pattern that translates across the sensor FOV during calibration, rather than using static targets. This dynamic approach allows multiple measurements to be captured in a single calibration sequence, significantly reducing calibration time while maintaining measurement accuracy through the accumulation of multiple frame data

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The calibration process uses periodic modulation of the target pattern through chopper modulation, alternating between open and closed states. This periodic action enables separation of signal from background and facilitates accurate PSF measurement by creating distinct measurement phases within the calibration sequence

Inventive Principle:
Principle #19Periodic action

2Measurement precision

If conventional blur-calibration methods are used, then calibration can be performed, but the process is expensive

Engineering Contradiction:
ImprovePSF measurement accuracyVSAvoidcalibration cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent creates multiple copies of the target pattern across different spatial positions and temporal frames. By capturing the moving target pattern across multiple frames and synthesizing a high-resolution composite image, the system obtains accurate PSF measurements without requiring expensive specialized calibration equipment or multiple physical targets

Inventive Principle:
Principle #26Copying

3Measurement precision

If precision collimated patterns are projected to fill the sensor FOV, then PSF measurement precision is improved, but the system complexity and cost increase

Engineering Contradiction:
ImprovePSF measurement precisionVSAvoidcalibration system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

Instead of projecting complex static collimated patterns, the system uses a moving target pattern that naturally fills the FOV through translation. This dynamic approach achieves full FOV coverage with simpler optics, as the target's motion provides the necessary spatial distribution without requiring complex projection systems

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The moving target pattern serves multiple functions simultaneously: it provides spatial sampling across the FOV, temporal sampling through frame sequences, and contrast modulation through chopper operation. This multi-functionality eliminates the need for separate calibration components for each measurement dimension, reducing overall system complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP2748767B1Blur-calibration system for electro-optical sensors and method using a moving multi-target constellation
Publication Date: 2022.12.21 RAYTHEON CO
  • EP2748767B1 patent drawingFigure 1~2
  • EP2748767B1 patent drawingFigure 3~4

AI summary

Embodiments of a system and method for blur-calibration of an imaging sensor using a moving constellation are generally described herein. In some embodiments, blur-calibration of an imaging sensor includes moving a known target pattern across the field-of view (FaV) of the imaging sensor to present the target pattern across different frames at different pixel phases. Frames of images of the moving target pattern as seen in the FaV of the imaging sensor are captured to generate image data output. The image data output may be subsequently processed to generate data products representative of a shape of a point-spread function (PSF) from a high-resolution composite image generated from the captured frames. A chopper modulation may be applied to the moving target sequence and separate chopper-open and chopper-closed composite images are created.